INTRODUCTION:Pulmonary Langerhan’s cell histiocytosis is a rare but an important form of interstital lung disease presenting as multiple pulmonary nodules in adult cigarette smokers. In rare instances , it can mimic metastatic disease in cancer survivors who continue to smoke.
CASE PRESENTATION:1.A 46-year-old female current smoker was referred for evaluation of multiple nodules on chest CT scan. She had undergone radical mastectomy with axillary lymph node dissection of her left breast fifteen years ago for left breast adenocarcinoma. At that time she underwent chemotherapy, chest wall irradiation and hormonal treatment. At this presentation she was found to have a new lump on her right breast and multiple bilateral sub centimeter nodules on chest CT. She denied cough, fever, chills, sputum production, and shortness of breath or weight change. Biopsy of the right breast lump showed no malignancy. A wedge resection of the left upper lobe showed pulmonary Langerhans’ cell Histiocytosis (PLCH), confirmed by CD1a immunostaining. No malignancy or infection was detected. 2.A 51-year-old female smoker was referred for evaluation of an abnormal chest X-ray detected during a three monthly follow up of resected stage 1a carcinoid tumor from left lower lobe preformed nine months prior to the current presentation. Her only complaint was a chronic dry cough. The HRCT scan of the chest showed innumerable bilateral micronodules ranging from sub centimeter to one centimeter in size. A transbronchial biopsy of left upper lobe showed diagnostic features of PLCH. She was counseled on smoking cessation but did not manage to quit. Follow-up CT performed 6 and 18 months following diagnosis showed marked decrease in the nodular changes and pulmonary function testing revealed a 390ml improvement in Vital Capacity.
DISCUSSIONS:Pulmonary LCH is an unusual but important cause of diffuse lung disease that typically occurs in relatively young adult smokers. Pulmonary LCH can predate, occur concurrently or present several years following the diagnosis of malignancy, as illustrated by our cases. The detection of lung nodules in cancer patients is usually an ominous sign representing metastatic disease. Occasionally, lung nodules may represent an inflammatory process such as LCH, sarcoid or bronchiolitis obliterans organizing pneumonia. Since neither of our patients had cystic change on imaging, lung biopsy was necessary to establish definitive diagnosis. It is possible that in patients with cancer, PLCH may represent an abnormal dendritic cell response triggered by endogenous anti-tumor responses coupled with antigenic stimulation from cigarette smoke. Smoking cessation is essential to prevent progression of disease, although spontaneous remission with resolution of lung nodules and stability in lung function may occur, even in the context of continued tobacco exposure, as illustrated by the second case.
CONCLUSION:PCLH is an uncommon but an important disease mimicking metastatic disease in adult smokers.
DISCLOSURE:Rajesh Patel, No Financial Disclosure Information; No Product/Research Disclosure Information